Changes in the bid documents were not unexpected, as the city has been negotiating with potential bidders since the first draft lease was created in October.

"It's always been a fluid document, a fluid proposal," said council President Julio Guridy. "The city has invested a lot of money doing their due diligence, and of course the concessionaires are also trying to make sure they get the best deal possible."

But Councilwoman Jeanette Eichenwald, the most vocal opponent to the lease, said the changes are troubling, and she cannot understand how any of her collagues could support the proposal.

"The document really bears little resemblance to the mayor's original presentation," she said. "To me that's not good governance, when you make a presentation, talk about it to everyone, and then it comes back completely different."

Rate cap increased

Mayor Ed Pawlowski originally said there would be no rate increases the first three years of the 50-year agreement, then subsequent hikes would be tied to the consumer price index.

That is still the case, but now the leasee would be allowed to raise rates 2.5 percent beyond the CPI from 2016 to 2032, then 2 percent above it from 2033 onward.

Under the draft proposal announced in October, rate caps prevented an operator from raising rates more than 1.5 percent beyond the CPI after 2032.

The 20-year CPI average has been 2.5 percent. If that were the index in a year between 2016, rates would rise by 5 percent. If it were after 2032, they would rise 4.5 percent.

Also new in the bid documents, additional service charges could be imposed if the state takes jurisdiction over the water and sewer systems and costs the private operator revenue.